set task limit
add record monitor call back & small modifications
- record monitor: check if record is data
- modifications: collector should have unlimited scheduling cycle,
  default: unlimited scheduling cycle
allow user to set negative demand limit
  - use flag -nd <num>
Two important bug fixes for race conditions in S-Net reference counting.
Make fix for two race conditions dependent on presence of
HAVE_SYNC_ATOMIC_BUILTINS.  Add comments to explain the situation.
Merge pull request #47 from gijsbers/master

Improve configure.ac, logging and C4SNet
Merge branch 'master' of https://github.com/snetdev/snet-rts
- remove redundant variable & update LPEL_FLAGS
 + dloc_placement is removed as it is not used in LPEL_HRC
Merge pull request #49 from nguyenvuthiennga/master

small modifications & add user-defined option in LPEL HRC
Merge Distributed Front from branch 'par'.
Merge remote-tracking branch 'upstream/master'
Make feedback work for Distributed Front.
Avoid the need for a stack reversal when deserialising.